This invention relates to a mould side system for concrete casts, which system comprises side sections, which can be detachably fastened to a casting bed using one or several magnets. In particular, the invention relates to an uncomplicated magnet unit.
Detachable sides for concrete element casting moulds, provided with various fastening designs, are known in the art. The sides can be assembled on the casting bed in desired locations depending on the size and shape of the object to be cast.
When concrete wall elements are cast, a bed mould or turning mould with sides is normally used. The casting machine moves above the bed and dispenses concrete mass into the mould. When the cast is hardened, the bed is tilted around an axis along one edge into an almost upright position, the upper mould side is removed and the element is lifted away from the bed using links in its side. The position of the upper mould must be adjustable according to the size of the cast element, and for this purpose detachable sides may be used. With the help of detachable mould side units, which may be freely positioned, openings can also be formed in desired parts of the element.
The use of magnets for fastening detachable mould side units is known, and magnets are well suited for side fastening as they adhere to the flat steel surface of the casting bed. In order to achieve a firm bond, strong magnets providing a bonding force of e.g. 15 kN must be used. In EP 1 075 917, a magnet unit is disclosed which attaches itself to a counterpiece in the mould side by means of a slanted protrusion or jaw on its front face, said protrusion biting into a corresponding slanted notch in the counterpiece. The front face of the magnet unit is designed to provide a precise 90xc2x0 angle in respect to the casting bed when the magnet unit is fastened to the mould side, whereby the front face attaches itself firmly to the rear surface of the mould side and holds it upright, due to the wedging notch action characteristic to the fastening system. In the magnet unit according to EP 1 075 917, a tilting magnet is provided which can be either in a lower position attached to the casting bed, or in an upper, standby position. To detach the magnet from the casting bed and tilt it to the standby position, a dual action lever is used.
The invention provides a straightforward and veratile system particularly for fastening mould sides for low (5-120 mm) facade slabs. The magnet unit according to the invention has no movable parts, but the magnet is a fixed component of the unit and detaching is carried out using a simple lever tool. The fastening of the mould side to the magnet unit takes place using the jaw principle known from EP 1 075 917.
Due to the uncomplicated design of the magnet unit, several faces for fastening mould sides can be provided on the unit. When double sided magnet units according to claim 3 are used, several parallel moulds can be assembled on a small area, whereby adjacent mould sides are supported by common magnet units.
Together with the magnet unit according to the invention, a smooth-face jaw mould side is used, preferably having a continuous counter-wedge surface for the magnet unit. The relevant profile can be produced by the meter and cut into individual lengths. The profile may constitute a mould side either as such or, for example, be provided with a plywood surface. It may be constructed in one piece of from separate parts. Due to the guiding counter-wedge in the mould side, various slots in the cast are easily produced using reinforcement sections.
The internal forces of the system make the interface of the mould side and the magnet unit completely rigid. When in position, the magnet body acts as a spring element as the magnet is pulled towards the bed. The mould side strives to seal, by its front edge, the joint between the mould side and the casting bed, and resists any tendency of the side falling backwards.
Assembly is quick and easy, and the fastening position may be selected at will, steplessly. By this method of fastening, the positioning of the mould in exactly the right position is enabled, as well as detachment of the magnet unit without displacing the mould side.
An important property of the magnet unit according to the invention is, that it can be positioned at the joints of the mould side units, whereby it both connects the side units together and attaches them to the casting bed. Corner joints can also be made using appropriate fastening adaptors.
In a system according to the invention, ready-made mould side and magnet units can be kept in stock, which units can be readily combined to form the required furnishings. Present-day requirements relating to ergonomics and automation have also been taken into account (low weight, smooth surfaces, ease of cleaning, robot handling). The mould side is best manufactured from special strength steel. Also, extruded aluminium, light metal, plastics or the like can be used. The shape of the mould side enables robot handling in moving and storage of mould side units.